JPS6340238A - Fluorescent display tube - Google Patents

Abstract

PURPOSE:To reduce a space between phosphor layers and improve display quality by coating the surfaces of graphite electrodes with the phosphor layers having similar areas. CONSTITUTION:Phosphor paste in a zinc oxide family is applied to the surfaces of graphite electrodes 4 with the position, size and shape similar to those of graphite electrodes 4 by a printing method and fired at about 500 deg.C to form phosphor layers 5. Thereby, an anode substrate 10 can be obtained. The minimum value of a space between two neighboring phosphor layers 5 is made to be equal to the space between the graphite electrodes 4. The anode substrate 10 obtained in this way, a grid 6, filaments 7 and a cover glass 8 are assembled and sealed to obtain a fluorescent display tube having a small space between neighboring two phosphor layers 5 and the excellent display quality.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to the structure of a fluorescent display tube that displays numbers, symbols, 0 patterns, etc. by emitting light from a fluorescent substance.

[Conventional technology]

Conventionally, this type of fluorescent display tube has a power supply line 2 formed of Ag or Al on an insulating substrate 1, as shown in FIG. An insulating layer 8 made of pigment is provided, and a graphite electrode 4 is formed at a position corresponding to the through hole, and a phosphor 1-5 is deposited thereon by screen printing in an area smaller than the graphite electrode 4. A phosphor layer 5 of an anode substrate 10 consisting of an anode, a grid 6 disposed at a corresponding position at an appropriate distance from the anode, and a grid 6 disposed at an appropriate distance from the grid 6. A structure is provided in which a filament 7 and a cover glass 8 whose inner surface is coated with a transparent conductive film are sealed to an anode substrate 10 to form a vacuum-tight container. However, in this structure, since the phosphor layer 5 is smaller than the graphite electrode 4, it is difficult to make the interval between adjacent phosphor layers smaller than 0.3 mm, and the display pattern If a white zinc oxide-based phosphor and a white insulating material are selected for the purpose of highlighting the phosphor layer 5, a black border will appear around the phosphor layer 5 due to the electrode 4, and the quality of the appearance will deteriorate. There are disadvantages that are not desirable.

In order to solve these problems, the graphite electrode 4 and the phosphor layer have the same area as shown in Figure 2 (c), and the phosphor layer 7 m 5 is larger than the graphite electrode as shown in Figure 2 (c). Each structure has been proposed.

[Problem that the invention seeks to solve]

In the structure of the conventional fluorescent display tube described above, the one shown in FIG. 2(a) cannot reduce the distance between adjacent phosphor layers;
And, the graphite electrode has the drawback that a black border appears on the graphite electrode, and in the case of the one shown in Fig. 2 cb), it is difficult to print the phosphor layer.
The disadvantage is that the display quality is significantly degraded due to bleeding in the peripheral area of the phosphor layer, and in the case of Figure 2<c, the potential distribution in the peripheral area of the phosphor layer is uneven, especially when using zinc oxide phosphor. If a phosphor having a relatively high electrical resistance other than the phosphor is used, there is a drawback that the display around the phosphor becomes dark.

[Means for solving problems]

In the fluorescent display tube of the present invention, a graphite electrode having a surface height flush with the surface of the insulating layer is formed in an opening provided at a portion of the insulating layer where the graphite electrode is formed;
A phosphor layer is deposited on the surface of the graphite electrode in the same area, and the insulating layer and the phosphor layer have the same color.

Therefore, since the phosphor layer is deposited on the graphite electrode with the same area, the phosphor layer, that is, the anode, can be installed with a small interval, and the black The disadvantages of deterioration of display quality due to fringing, blurring, etc., and of dark display in the vicinity of the phosphor due to non-uniform potential distribution around the phosphor are eliminated.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a partial cross-sectional view of one embodiment of the fluorescent display tube of the present invention. Power supply lines 2 are arranged on an insulating substrate 1 at necessary intervals, and are covered with an insulating layer 8 leaving an opening where a graphite electrode 4 is formed. In this opening, a graphite electrode 4 is formed with a surface height that is flush with the surface of the insulating layer 3, and a phosphor layer 5 is coated over the same area to form an anode substrate 10. Here, the phosphor layer 5
and the insulating layer 3 have almost the same white color. Further, the configuration other than the above is the same as that in FIG. 2(a).

Next, the manufacturing procedure of the fluorescent display tube of this example will be explained.

First, an A1 pattern having a thickness of 1 μm is deposited on a glass insulating substrate 1 by sputtering, and a power supply line 2 having a desired shape is formed by photolithography.

Next, a paste mainly composed of low-melting glass and pigment is applied thereon by a printing method except for the part where the graphite electrode 4 is to be formed, and is fired at 580°C to form a black insulating layer with a thickness of 30 μm. form 8. Next, graphite paste was applied by printing to the opening in the insulating layer 3 that was created by not applying the paste lr, that is, to the inner surface of the hole, matching the size and shape of the stone. A graphite electrode 4 having a thickness of 30 μm is provided in the same way as the insulating layer 8 by firing at 0.0 µm. The distance between two adjacent graphite electrodes 4, that is, the minimum value of the distance between two adjacent graphite electrodes 4 provided on the insulating layer 3 is Q, 2
It was set to 5m.

Furthermore, a graphite electrode 4 is placed on the graphite electrode 4.
The anode substrate 10 was obtained by applying a zinc oxide-based phosphor paste using a printing method and firing at 5,000 ℃ to form a light body R45 having the same position, size, and shape. The minimum distance between two adjacent phosphors 1-5 was equal to the distance between graphite electrodes 4, which was 0.25 mm.

By combining and sealing the thus obtained anode substrate 10, the grid 6, the filament 7, and the cover glass 8 using a known method, the distance between two adjacent phosphor layers is small, and a phosphor with excellent display quality is produced. A display tube was obtained.

In the embodiment described above, when the insulating layer 3 is white, the colors of the phosphor M5 and the insulating Nj8 are almost the same, and an entirely white anode substrate 10 with high display quality can be obtained.

〔Effect of the invention〕

As explained above, the present invention provides an opening in an insulating layer at a position where a graphite electrode is to be formed, and a graphite electrode is formed inside the opening with the surface height approximately the same as that of the insulating layer. By forming the phosphor layers, it is possible to obtain a phosphor display tube in which the distance between the phosphor layers is small and the display quality is high.

It is clear that any changes in the paste application method, material, other manufacturing processes, etc. do not depart from the spirit of the present invention.

[Brief explanation of the drawing]

FIG. 1 is a partial cross-sectional view showing the structure of a fluorescent display tube according to the present invention, and FIG. It is a sectional view. 1... Insulated substrate, 2... Power supply line, 3... Insulated fi
l, 4... Graphite electrode, 5... Fluorescent layer (anode), 6... Grid, 7... Filament, 8...
...Cover glass, 10... Anode substrate.

Claims (1)

[Claims] (1) A fluorescent display tube having an anode substrate comprising a power supply line disposed on an insulating substrate, an insulating layer covering the power supply line, and a graphite electrode on which a phosphor layer is adhered, the insulating A graphite electrode having a surface height substantially coplanar with the surface of the insulating layer is formed in an opening provided in a portion of the layer where the graphite electrode is formed, and the phosphor layer is disposed on the surface of the graphite electrode. A fluorescent display tube characterized in that the area is coated. 2) The fluorescent display tube according to claim 1, wherein the insulating layer and the phosphor layer have substantially the same color.